Limit snap gauge



Sept'. 30, 1924.

A. MELDRUM ET AL LIMIT SNAP GAUGE Filed April 1 Zaren/ar Patented Sept.30, 1924i.

ALEXANDER MELDRUM AND CARL GABRIELSON, 0F SYRACUSE, NEW YORK, AS-SIGNORS TO MELDRUM-G-ABRIELSON CORPORATION, GF SYRACUSE, NEW YORK, A

CORPORATION 0F NEW YORK.

LIMIT SNAP GAUGE.

Application led April 1,

To all 107mm t may concern:

Be it known that we, ALEXANDER MEL- DRUMY and CARL GABniELsoN, of thecity of Syracuse, in the county of Onondaga, State of New York, haveinvented certain new and useful Improvements in Limit Snap Gauges, ofwhich the following is a specification.

This invention relates to limit snap gauges for measuring the outsidedimen sions of work, and has particular reference to the form andstructural arrangement and mounting of the measuring pins in the frame.It embodies a simple structure by which the longitudinally adjustablemeasuring pins are held against rotation in the frame by the transverseshape and lateral engagement with the frame and which presents astraight edge to the work, and which, particularly in the preferredfoi-1n, has a working end surface of such form that the wear in use willbe uniform in character and of a minimum amount. The novel features willbe more fully understood from the following description and claim takenin connection with the drawing.

In the drawing,

Figure 1 is a side view of a gauge embodying the invention.

Figure 2 is a plan view looking down from the section line 2-2 of Figurel, and

Figure 3 is a cross section on theline 3 8 of Figure 1.

For purposes of illustration we have shown in Fig. l a frame 10 ofordinary and vell known horse shoe shape or form, carrying the measuringpins 1l mounted in sockets or openings through the arms of the framenear their ends. Two parallel pins are shown in each arm and as is wellknown, the pins on one arm are aligned with pins on the other arm, withthe working surfaces parallel facing each other. These measuring pinshave heretofore been made circular in section fitting a circular socketin the arm of the frame, and to prevent rotation of the pin whilepermitting longitudinal adjustment it has been necessary to use someseparate holding means such as a pin and slot connection. The projectingend of a round measuring pin furthermore normally presents a curved edgeto the work, which not only localizes the wear but may produce unduestrains causing injury 1921. Serial No. 457,729.

and wear unless great care is used, and it has been found that astraight edge for the pin facing the work is preferable. The presentinvention avoids the necessity for separate special means for holdlngthe pins against rotation by forming a portion of the Din, preferably atthe projecting end, non-circular in cross sectionA fitting a similarnon-circular portion of the socket so that by the shape and fit the pinmay be adjusted longitudinally but cannot turn in the socket. Thenon-circular projecting portion preferably has one flat longitudinalsurface facing the work so that whether beveled or not it will present astraight edge for contact with the work. In the preferred form shown,the non-circular portion of the pin 11 and its socket are made square insection, and the projecting portion is also rectangular in section withone side facing the work. It has been found that a symmetricalrectangular Contact surface wears more evenly and to a less extent thanother forms in use, and that thus regrinding is not required so often orto the same extent,

Referring specifically to Figures 2 and 3, the socket or hole 12 in theframe 10 has at its outlet end a portion 13 which is square in crosssection and which closely fits the projecting square end of pin 11, andone of its side walls presents a flat surface at substantially rightangles to the plane of the frame so that the matching side wall of pin11 projecting beyond it will face the work and present a straight linefor contact at its end. The longitudinal edges of the square portion maybe slightly beveled or ground to avoid sharp edges. It is of ad vantageto bevel the edge of the pin 11 facing the work as shown at 14 but thatstill leaves a straight edge for contact. The specific means shown forholding and longitudinally adjusting the pins in the sockets constituteno part of the present invention, as any suitable means for the purposemay be used. In the form shown, the inlet end of the socket or hole 12is internally screw threaded at 15 to receive the screw threaded sleeve16 having a central funnel shaped opening 17 adapted to permit the shankof screw 18 to pass through and to tit its tapering head. This screwthreaded portion is of sufficiently large diameter to permit the v u 2 Mpin 11 to freely pass down through it and it extends to a pointmaterially below the end of the pin when new so as to permit adjustmentfor Wear. The pin 11 has in its end a screw threaded socket 19 enteredand en gaged by the screw threaded shank of screw 18,` and thus thesleeve 17 and pin l1 may Having thus described the invention, what isclaimed as new and desired to be secured by Letters Patent 1s:

A limit snap gauge comprisingy a frame provided with opposite pinsockets and a measuring stud or gin in each socket having a portion.non-circu ar in cross section, nonrotatably litting and longitudinallymovable in a matching non-.circular portion of said socket with a Hatend work surface for measuring in a plane at right angles to the line ofmovement of the pin in the frame and having on the side facing the Worka flat surface presenting a straight edge at right angles to the line ofmovement to the Work, and a beveled surface connecting the Workingsurface and the flat surface facing the Work. l v

In testimony whereof we hereunto affix our signatures.

ALEXANDER MELDRUM.

CARL GABRIELSON.

